Treatment of steel ingots for forging.



UNITED STATES PATENT OFFICE.

CHARLES TARBELL DUDLEY, OF GOLDEN, COLORADO, ASSIGNOR OF ONE- FOURTH TOWILLIAM W. DUDLEY, FRANK L. BROWNE, AND WILLIAM T. NORTON, OFWASHINGTON, DISTRICT OF COLUMBIA.

TREATMENT OF STEEL INGOTS FOR FORGING.

SPECIFICATION forming part of Letters Patent No. 705,330, dated July 22,1902.

Application filed February 10, 1902 To all whom it may concern.-

Be it known that 1, CHARLES TARBELL DUD- LEY, a citizen of the UnitedStates, residing at Golden, in the county of Jefferson and.

State of Colorado, have invented certain new and useful Improvements inthe Treatment of Steel Ingots for Forging; and I do declare thefollowing to be a full, clear, and exact description of the invention,such as will enable others skilled in the art to which it appertains tomake and use the same.

This invention relates to the treatment of steel, and contemplates animproved process designed more especially for treating cast I 5nickel-steel ingots, with the object of preventing therein the formationof streaks, working cracks, and other defects which would develop in thesubsequent forging operation and impair the eiiiciency of the fin- 2oished product.

My improved process, which is carried into effect in advance of theforging step, operates by reducing the size of the grains or crystals ofthe steel to prevent the formation of the defects above stated, whichdefects are largely the result of the separating or breaking apart ofthe coarse crystals during the operation of forging.

The process may be advantageously em- 0 ployed in treating various kindsof ingots, billets,and the like, although, as stated above,

, it is designed mainly for'treating nickel-steel ingots which are castto be forged into the heavy grades of forgings, such as ordnance,

5 marine shafting, &c.

In practicing my improved process the cast ingot is allowed to coolbelow the critical temperature, (550 centigrade,) at which step thescrap is cut off, and, if desired, the ingot may 40 be divided intobillets. The ingot or billet is then placed in a suitable furnace andheated to a temperature between 750 centigrade and 850 centigrade,dependent upon the size of the ingot or billet, the larger the ingot or5 billet the higher the temperature required. This reheating temperatureis maintained for Serial No. 93,341. (No specimens.)

a period of time ranging from thirty to fortyfive hours, depending uponthe size of the ingot or billet, the larger the ingot or billet thelonger the time required, after which the ingot or billet is allowed tocool and subsequently reheated for the forging step, or, preferably, theingot or billet is directly brought to forging temperature and forgedwithout the intermediate cooling. The subjecting of the ingot or billetto the stated reheating temperature for the described length of timeresults in a reduction of the size of the steel crystals, at the sametime producing a perfectly homogeneous structure which can subsequentlybe safely forged without the formation of streaks and cracks and otherdefects which would impair the strength, utility, and appearance of thefinished product.

The ingots of the kind which my improved process is especially adaptedto treat have an approximate composition of from twenty-five below sixhundredths per cent. of phosphorus.

My invention is, however, applicable to the treatment of ingots andbillets of other compositions, and may be advantageously used intreating other than nickel-steel ingots and billets.

I claim as my invention The process of treating cast-steel ingots andthe like previous to forging, which consists in cooling the cast ingotto a temperature below 550 centigrade, reheating the cooled ingot to atemperature between 750 centigrade and 850 Centigrade, maintaining saidreheating temperature for a period of from thirty to forty-five hours,and finally heating the ingot to forging temperature.

In testimony whereof I affix my signature in presence of two Witnesses.

CHARLES TARBELL DUDLEY.

Witnesses:

A. H. GOLLBRAN, EUGENE H. DAWSON.

